1. Field of the Invention
The present invention relates to an apparatus for forming holes in a medium. More particularly, the invention relates to an automated apparatus for selectively forming a desired number of holes in the medium.
2. Description of Related Art
Documentation, such as paper sheets, often require holes punched therein for subsequent filing. For example, three ring binders are commonly used to retain 81/2.times.11 size paper. These binders require three holes of predetermined spacing formed in the left margin of the paper to be stored therein. Two and five ring binders are also known. On the other hand, legal size (11.times.14) paper is commonly retained by two rings or pins inserted through two holes formed in the top margin of the medium.
Manual or automated hole punching machines are wellknown for forming such holes in media. Typically, one or more sheets of paper are placed in these machines and the operator either manipulates a lever or presses a button to cause punching studs to cut through the paper and form the holes. Because the spacing between holes in standard two-hole and three-hole formats differs, certain manual hole punching machines allow the position of at least one punch to be adjusted to permit punching in either format. Typically, such adjustment is a tedious, time-consuming process that includes loosening clamps holding the punch in position, sliding the movable punch to the desired position and retightening the clamps. Switching between two- and three-hole punching in certain automated machines is much simpler, merely requiring the sliding of a switch. In some models, the switch also functions as a paper guide, the position of which differs depending on the size of the paper to be punched.
When the paper to be punched has an image formed thereon by a printer or a copier, an operator would typically remove the recorded paper from the discharge tray or sorter of the printer or copier, carry it to a separate punching machine and effect the punching process. In order to eliminate a number of steps in forming printed media with holes punched therein, it has been proposed to incorporate an automated hole punching mechanism disposed before or after the sorter or discharge tray in the medium conveying path of a printer or copier, for example. However, these apparatuses cannot readily switch between forming different numbers of holes in the recorded media. That is, the punching mechanism has to be reconfigured if three holes are to be formed in the discharged media rather than two holes, for example.